Non-resonant frequency components observed in a dynamic Atomic Force Microscope

Abstract

The oscillating behavior of a micro-cantilever probe plays a central role in the atomic force microscope for studying a nanoscale sample. The oscillatory phenomena in the microscope are numerically investigated by exciting the probe with a single frequency. We observe the non-resonant frequency components, which correspond to a frequency of transient beats superimposed on the stable solution, around the natural frequency of the probe, when the probe is close to the sample. The difference between the non-resonant frequency and the natural frequency changes when the tip-sample distance decreases. Furthermore, we investigate the originating point of the non-resonant frequency components as a function of the tip-sample distance. In addition, we perform an actual experiment for observing the frequency components near the resonant frequency.

Amplitude Decaying Characteristic in a One-Dimensional Continuous Microcantilever Probe Model

“…In this study, we assume that both the interaction and the external sinusoidal forces are injected into the probe and investigate the amplitude characteristic of the probe oscillation when the interaction force between the probe and the sample surface increases. In particular, we show that monotonically decaying amplitude characteristics appear in the higher oscillation modes, which are qualitatively consistent with the properties of the fundamental oscillation mode [6].…”

Influence of a Heterogeneous Sample Surface on a Driven Microcantilever Probe Model

“…It is known that the tip-oscillation has two coexisting solutions when the distance between the tip and sample becomes small [6]. One is a solution in which the tip does not contact with the sample, while the other is a solution in which the tip contacts intermittently with the sample surface.…”

“…When the probe tip is driven by an external force l cos(ωt) [m] at a distance z 0 [m] from the sample surface, the lateral oscillation z ′ [m] , which is shown in Fig. 1, is written as follows [6]:…”

“…A scanning probe microscope (SPM) is a microscope that measures the information of a sample surface when the probe tip approaches the surface. Owing to the necessity of obtaining the information of microscopic samples, such as nanoscale semiconductor devices, studies on the mechanical behavior of the probe tip have attracted considerable research interests [1][2][3][4][5][6]. Dynamic atomic force microscope (dAFM) is one type of SPM.…”

“…In our previous work, we investigated a mass-spring model of the driven probe tip influenced by a homogeneous sample [6]. In this study, we investigate the influence of a heterogeneous sample surface on the amplitude characteristic of the tip oscillation.…”